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https://github.com/maxisam/ngx-progressive-image-loader
lazy load img/picture, prevent reflow and seo friendly.
https://github.com/maxisam/ngx-progressive-image-loader
angular image-lazy-load lazyload lazyload-images progressive-image
Last synced: 6 days ago
JSON representation
lazy load img/picture, prevent reflow and seo friendly.
- Host: GitHub
- URL: https://github.com/maxisam/ngx-progressive-image-loader
- Owner: maxisam
- License: mit
- Created: 2018-08-13T11:12:34.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-01-07T03:56:36.000Z (almost 2 years ago)
- Last Synced: 2024-10-05T16:09:28.891Z (about 1 month ago)
- Topics: angular, image-lazy-load, lazyload, lazyload-images, progressive-image
- Language: TypeScript
- Homepage:
- Size: 14 MB
- Stars: 35
- Watchers: 3
- Forks: 6
- Open Issues: 33
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://travis-ci.org/maxisam/ngx-progressive-image-loader)
[](https://www.npmjs.com/package/ngx-progressive-image-loader)
[](https://github.com/maxisam/ngx-progressive-image-loader/releases)
[]()
# ngx-progressive-image-loader
Support Angular >=6.0.0
## Demo
[stackblitz.com](https://stackblitz.com/github/maxisam/ngx-progressive-image-loader)
## Features
- No other JS dependency. Just Angular
- Use **IntersectionObserver** to determine the timing to load the image
- Support image and picture
- Preserve space to avoid dom reflow
- Show small default loading image with fading transition
- Load image directly for spider (SEO friendly) or non-supported browsers
- Aggressive Loading. Able to continue to load even if images haven't got intersected when the concurrently loading count is lower than a certain value. (_after 4.0.0_)
## Install
```bat
npm install ngx-progressive-image-loader --save
```
Open your module file e.g `app.module.ts` and update **imports** array
```ts
import { NgxProgressiveImageLoaderModule, IImageLoaderOptions } from 'ngx-progressive-image-loader';
...
imports: [
...
NgxProgressiveImageLoaderModule.forRoot({
// rootMargin must be specified in pixels or percent
rootMargin: '30px',
threshold: 0.1,
// css filter
filter: 'blur(3px) drop-shadow(0 0 0.75rem crimson)',
// image width / height ratio for image holder
imageRatio: 16 / 9,
// loading image in placeholder. Can be URL or base64
placeholderImageSrc:
// tslint:disable-next-line:max-line-length
'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAyNTAgMjUwIj4KICA8cGF0aCBmaWxsPSIjZGQwMDMxIiBkPSJNMTI1IDMwTDMxLjkgNjMuMmwxNC4yIDEyMy4xTDEyNSAyMzBsNzguOS00My43IDE0LjItMTIzLjF6Ii8+CiAgPHBhdGggZmlsbD0iI2MzMDAyZiIgZD0iTTEyNSAzMHYyMi4yLS4xVjIzMGw3OC45LTQzLjcgMTQuMi0xMjMuMUwxMjUgMzB6Ii8+CiAgPHBhdGggZD0iTTEyNSA1Mi4xTDY2LjggMTgyLjZoMjEuN2wxMS43LTI5LjJoNDkuNGwxMS43IDI5LjJIMTgzTDEyNSA1Mi4xem0xNyA4My4zaC0zNGwxNy00MC45IDE3IDQwLjl6IiBmaWxsPSIjZmZmIi8+Cjwvc3ZnPgo='
})
...
]
```
Add style to your global scss
```scss
@import '~ngx-progressive-image-loader/ngx-progressive-image-loader';
$scale: 0.5; // the scale of loading image in place holder
$transition: opacity 1s linear; // the transition of loading image in place holder, you could try: opacity .3s ease
@include progressive-image-loader($scale, $transition);
```
## Usage
- with img
```html
![]()
```
- with img + srcset
```html
![]()
```
- with picture element
```html
![My default image]()
```
## Configuration for IImageLoaderOptions
[Intersection_observer_options](https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API#Intersection_observer_options)
- root
The element that is used as the viewport for checking visiblity of the target. Must be the ancestor of the target. Defaults to the browser viewport if not specified or if null.
- rootMargin
Margin around the root. Can have values similar to the CSS margin property, e.g. "10px 20px 30px 40px" (top, right, bottom, left). The values can be percentages. This set of values serves to grow or shrink each side of the root element's bounding box before computing intersections. Defaults to all zeros.
- threshold
Either a single number or an array of numbers which indicate at what percentage of the target's visibility the observer's callback should be executed. If you only want to detect when visibility passes the 50% mark, you can use a value of 0.5. If you want the callback run every time visibility passes another 25%, you would specify the array [0, 0.25, 0.5, 0.75, 1]. The default is 0 (meaning as soon as even one pixel is visible, the callback will be run). A value of 1.0 means that the threshold isn't considered passed until every pixel is visible.
- filter
If you want to set more [filter](https://developer.mozilla.org/en-US/docs/Web/CSS/filter). It uses the input string as css filter.
- placeholderImageSrc
src for loading image. It works just like src, takes base64 or url.
- imageRatio
image width / height
For `ngx-image-placeholder` component, it takes
- imageRatio
- placeholderImageSrc
(_after 3.0.0_, you can set imageRatio and placeholderImageSrc directly on `ngxProgressiveImage` and spare ngx-image-placeholder layer)
For `ngx-progressive-image-loader` component, it takes
- imageRatio
- placeholderImageSrc
- filter
- isAggressiveLoading: boolean; default to `true`; Set to `true` to enable **Aggressive Loading** feature. (_after 4.0.0_)
- concurrentLoading: number; default t0 4; Decided at least how many concurrent loading when **Aggressive Loading** is enabled
For `ngxProgressiveImage` directive, (only for image or source elements)
- imageRatio
- placeholderImageSrc
- noPlaceholder: boolean; default to `false`, set to `true` will skip image placeholder
## Build project
```bat
npm i
npm run build
```
To run demo code locally
`npm run start`
## Browser Compatibility
Browsers don't support Intersection Observer API will not work as expect. It will load images like old time.
Use [pollyfill](https://github.com/w3c/IntersectionObserver/tree/master/polyfill) like below might make it work.
```html
```
## Contributing
- Your commits conform to the conventions established [here](https://github.com/conventional-changelog/conventional-changelog-angular/blob/master/convention.md)
## Troubleshooting
Please ask your general questions at https://stackoverflow.com
## Shoutouts 🙏
This project was generated with [Angular CLI](https://github.com/angular/angular-cli) version 6.2.0 beta 02.
Kudos to the following authors:
https://deanhume.com/lazy-loading-images-using-intersection-observer/
https://www.voorhoede.nl/en/blog/say-no-to-image-reflow/
https://jmperezperez.com/medium-image-progressive-loading-placeholder/
https://github.com/verlok/lazyload for detecting spider
And my wife and my child to let me work on a weekend for this.
Big thanks to [BrowserStack](https://www.browserstack.com) for letting the maintainers use their service to debug browser issues.